【单选题】

How and why would strain and anxiety trigger some of us to pile on extra weight Stress activates the flight-or-fight response (应激反应), a physiological reaction designed to get your body moving quickly in a physical emergency. When your brain perceives a threat, it sounds the alarm to your adrenal glands (肾上腺) to pump out the stress hormone cortisol (皮质醇). The hormone then signals fat cells to quickly release energy, which your muscles can use for a surge of power to "flee" or "fight". When the danger passes, cortisol briefly stays elevated to encourage your body to replenish (补充) its fat stores, then returns to normal.

"The system works beautifully if you’re running for the last bus home after work. It gives you a burst of energy, which you recover from quickly once you take your seat," says Pamela Peeke, MD, clinical assistant professor of medicine and author ofBody for Life for Women.But when you turn on the stress response for months on end—worrying about your marriage or mortgage payments—you do damage. "Then, cortisol levels remain persistently elevated, persistently signaling your body to store fat," saysDr. Peeke.
This mechanism may also affect where flab (松弛) builds up on your body. Under stress, women who carry excess weight in their abdominal area secreted (分泌) significantly more cortisol than women who didn’t have extra belly fat, according to a study from the University ofCalifornia at San Francisco.And since deep abdominal fat tissue has up to four times the number of receptors for cortisol as does superficial fat elsewhere in the body, the cells in this area are the most likely to respond and store fat when exposed to extra stress-induced cortisol. Unfortunately, this extra abdominal flab isn’t just a cosmetic concern; it is strongly linked to a greater risk of heart disease and stroke, two top killers of women over 50.
The cumulative (累积的) effects of the stress-fat connection can be great.Although you can’t control many of the things that cause you stress, you can take steps to curb the negative effect these stressors have on your body. "Support is essential. Reach out to family and friends," saysAliceDomar, PhD, director of the Mind/BodyCenter for Women’s Health atBoston IVF.
The main purpose of this passage is to ______.
A、tell us how to reduce pressure appropriately
B、reveal the reason why some women have extra belly fat
C、teach us how to avoid the negative effect of stress
D、explain how and why strain and anxiety would make some of us fatter